<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<script>
    function find(arr,target) {
        for(let i of arr){
            if(i.constructor === Array){
                find(i,target)
            }else{
                if(i === target){
                    document.write('find');
                    return;
                }
            }
        }
    }

    let test = [
        [1, 3, 5, 7],
        [10, 11, 16, 20],
        [23, 30, 34, 50],
        [23, 30, 34, [1,3,4,90]],
    ];

    // let res = false;
    let res = find(test,90);



</script>

</body>
</html>